The relationship between nations and IQ is a controversial area of study concerning differences between nations in average intelligence test scores, their possible causes, and their correlation with measures of social well-being and economic prosperity. This debate started in the early 2000's after Richard Lynn and Tatu Vanhanen constructed and published IQ estimates for many countries using literature reviews, student assessment studies and other methodologies. Their results and conclusions caused significant controversy, and their approach has been criticized on theoretical and methodological grounds. Subsequent research by psychologists such as Earl B. Hunt, Jelte Wicherts and Heiner Rindermann has focused on identifying potential national differences in IQ, investigating possible causal factors, and determining the nature of the relationship of IQ to variables such as GDP, life expectancy, and governance. Source: Wikipedia (en)